Recent advances in intravenous calcitriol treatment.

Ten years after the pioneering data by Slatopolsky, there is growing evidence that calcitriol given intravenously is able to improve secondary hyperparathyroidism better than the traditional daily oral administration. However, the scenario is changing again after the observation that oral bolus therapy, in equivalent doses to the intravenous route, is also able to effectively control parathyroid hormone secretion. This review reports and comments on the most recent controlled and uncontrolled observations dealing with calcitriol therapy of hyperparathyroidism in patients with uremia. There are currently no convincing data about the superiority of one route of administration over the other, although intravenous boluses appear to be more attractive both from a theoretical (higher plasma levels and reduced action on intestinal receptors) and practical (compliance) point of view. The higher cost of the injectable drug is the crucial factor limiting its wider clinical use. Large and carefully designed controlled clinical trials are still awaited to elucidate the most important aspects of calcitriol treatment of secondary hyperparathyroidism, such as dose, interval, and route of administration.